Add docker-compose dev

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

Dockerfile

@@ -0,0 +1,11 @@
+FROM elixir:1.6
+
+RUN apt-get update && apt-get install -y build-essential inotify-tools postgresql-client
+
+RUN mix local.hex --force && mix local.rebar --force
+
+COPY docker/entrypoint.sh /bin/entrypoint
+
+WORKDIR /app
+
+EXPOSE 4000